import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.zip.GZIPOutputStream;
public class Main {
public static void main(String[] args) throws Exception {
InputStream fin = new FileInputStream("a.dat");
OutputStream fout = new FileOutputStream("a.dat.gz");
GZIPOutputStream gzout = new GZIPOutputStream(fout);
for (int c = fin.read(); c != -1; c = fin.read()) {
gzout.write(c);
}
gzout.close();
}
}